Air conditioning apparatus

ABSTRACT

Provided is an air conditioning apparatus, including a unit main body in which a heat exchanger and at least one blower fan are provided. The heat exchanger is arranged on an upstream side of the blower fan. The blower fan includes an impeller, a motor, and a fan casing. The impeller is a turbofan that sucks air from an upper portion thereof and blows out the air radially outward. A rotation axis of the impeller is directed to a unit height direction. The fan casing has a fan air inlet formed in an upper surface thereof, and has a fan air outlet formed in a lower surface thereof. An impeller air outlet of the impeller is covered by side surfaces of the fan casing.

TECHNICAL FIELD

The present invention relates to an air conditioning apparatus.

BACKGROUND ART

Patent Literature 1 and Patent Literature 2 disclose air conditioningapparatus of a downward-blowing type, which are used forair-conditioning a computer room and the like. Patent Literature 1 andPatent Literature 2 disclose the air conditioning apparatus each havingsuch a configuration that a V-shaped or inverted V-shaped heat exchangeris arranged on an upstream side of a blower fan. The blower fan includesa plurality of impellers, a plurality of volute fan casings arrangedaround the corresponding impellers, and a motor for driving theimpellers. Each of the impellers is arranged so that a rotation axisthereof is directed to a horizontal direction. Further, air inlets ofthe blower fan are directed sideways, and air outlets of the blower fanare directed downward. The plurality of impellers are driven by onemotor.

In each of the air conditioning apparatus, the air is sucked from a unitair inlet formed in an upper surface of a unit, and the air that isconditioned into a desired state is blown out from a unit air outletformed in a lower surface of the unit, toward an underfloor space inwhich the air conditioning apparatus is placed. The air passes throughthe underfloor space and gradually flows out upward from a surface of afloor, and thus a computer and a room are subjected to anair-conditioning effect.

Further, Patent Literature 3 discloses an air conditioning apparatus inwhich two heat exchangers are arranged in an inverted V-shape so thatlower portions of the heat exchangers are spaced apart from each other.Side block plates are arranged on both side surfaces of the two heatexchangers, and an upper block plate is arranged on upper portions ofthe two heat exchangers. Drain pans for collecting dew condensationwater are arranged below the heat exchangers, respectively. A blowerfan, which is arranged inside a unit, sucks the air from a unit airinlet formed in a lower portion of the unit. After the blower fan causesthe sucked air to pass through the heat exchangers arranged in aninverted V-shape as described above, and then subjects the sucked air todesired heat exchange, the blower fan blows out the air from a unit airoutlet formed in an upper portion of the unit, and blows out the airtoward an air outlet duct provided to the unit air outlet. Further, theblower fan is configured so that a fan air inlet thereof is directed toa side surface of the unit and a fan air outlet thereof is directed toan upper surface of the unit.

CITATION LIST Patent Literature

[PTL 1] JP 6-12465 Y2 (pp. 1 and 2, FIG. 2)

[PTL 2] JP 2011-202821 A (pp. 5 to 7, FIG. 2)

[PTL 3] JP 9-273801 A (pp. 2 and 3, FIGS. 1)

SUMMARY OF INVENTION Technical Problems

However, the above-mentioned related-art air conditioning apparatus havethe following problems.

First, in the air conditioning apparatus disclosed in Patent Literatures1 and 2, there is a problem in that, when an airflow blown out from theimpellers collides with the underfloor space, airflow resistance is highparticularly in a place where a height of the underfloor space is low,and hence power consumption of the motor is increased. Further, theblown-out airflow may stir up dust underneath the floor.

Further, in the air conditioning apparatus disclosed in PatentLiterature 3, there is a problem in that, when an airflow blown out fromthe impeller flows into and collides with the air outlet duct providedto the unit air outlet, airflow resistance is high, and hence powerconsumption of a motor is increased.

The present invention has been made in view of the above-mentionedproblems, and has an object to provide an air conditioning apparatuscapable of reducing power consumption of a motor along with reduction inairflow resistance.

Solution to Problems

In order to achieve the above-mentioned object, according to oneembodiment of the present invention, there is provided an airconditioning apparatus, including: a unit main body; a heat exchanger;and at least one blower fan. The heat exchanger is arranged on anupstream side of the blower fan. The blower fan includes an impeller, amotor, and a fan casing. The impeller is a turbofan that sucks air froman upper portion thereof and blows out the air radially outward. Arotation axis of the impeller is directed to a unit height direction.The fan casing has a fan air inlet formed in an upper surface thereof,and has a fan air outlet formed in a lower surface thereof. An impellerair outlet of the impeller is covered by side surfaces of the fancasing.

The blower fan may be arranged below the heat exchanger.

The impeller may include a plurality of blades, a side plate having aring shape, and a main plate, the side plate may be positioned on thefan air inlet side, the main plate may be positioned on the fan airoutlet side, and an outer diameter φDs of the side plate may be largerthan an outer diameter φDm of the main plate.

An outer diameter φDb1 of each of the blades on the side plate side maybe larger than an outer diameter φDb2 of each of the blades on the mainplate side.

The blower fan may include a plurality of blower fans.

The plurality of blower fans may be arranged with an interval in awidthwise direction.

The plurality of blower fans may be controlled so as to have mutuallydifferent numbers of revolutions of the fans.

The fan casing may include a frame body, and at least one side wallsurface removably mounted to the frame body.

The blower fan may include a motor support for supporting the motor, andthe motor support may be positioned closer to a side on which the fanair outlet is formed than the main plate of the impeller.

The side surfaces of the fan casing may include at least one flatsurface.

The fan casing may include at least one chamfered portion that, withreference to a rectangular shape of the fan casing in plane view, at aportion corresponding to a corner of the rectangular shape.

The heat exchanger may have a shape including at least one bent portion.

The heat exchanger may have an inverted V-shape or an M-shape.

Advantageous Effects of Invention

According to the one embodiment of the present invention, reduction inpower consumption of the motor along with reduction in airflowresistance can be achieved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an external perspective view illustrating an air conditioningapparatus according to a first embodiment of the present invention.

FIG. 2 is a side longitudinal cross-sectional view illustrating the airconditioning apparatus of FIG. 1.

FIG. 3 is a front longitudinal cross-sectional view illustrating the airconditioning apparatus of FIG. 1.

FIG. 4 is a perspective view illustrating a blower fan of the airconditioning apparatus of FIG. 1.

FIG. 5 is a cross-sectional view taken along the line V-V of FIG. 2.

FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 5.

FIG. 7 is a view schematically illustrating an airflow formed inside theblower fan of FIG. 4.

FIG. 8 is a view illustrating a second embodiment of the presentinvention and corresponding to FIG. 5.

FIG. 9 is a view illustrating a third embodiment of the presentinvention and corresponding to FIG. 2.

FIG. 10 is a view illustrating a modified example of the thirdembodiment and corresponding to FIG. 3.

FIG. 11 is a view illustrating the modified example of the thirdembodiment and corresponding to FIG. 2.

DESCRIPTION OF EMBODIMENTS

Now, an air conditioning apparatus according to embodiments of thepresent invention is described with reference to the accompanyingdrawings. Note that, in the drawings, the same reference symbolsrepresent the same or corresponding parts. The air conditioningapparatus according to the embodiments of the present invention can beused for, as an example, a computer room in which air cleaning,dehumidifying, and air-cooling are performed.

First Embodiment

FIG. 1 is an external perspective view illustrating an air conditioningapparatus according to a first embodiment of the present invention. FIG.2 is a side longitudinal cross-sectional view illustrating the airconditioning apparatus of FIG. 1, and FIG. 3 is a front longitudinalcross-sectional view illustrating the air conditioning apparatus of FIG.1.

In FIGS. 1 to 3, a contour of a unit main body 100 is formed in such amanner that a main body top plate 100 a having a unit air inlet 101formed in an upper surface of the main body, main body side plates 100b, and a main body bottom plate 100 c having a unit air outlet 102formed in a lower surface of the main body are mounted to a main bodyframe 100 d. Each of the main body side plates 100 b is divided so as tohave a configuration capable of being dismounted separately formaintenance of an inside of the main body.

Further, the unit main body 100 is arranged between a ceiling 121 and afloor 118 of a room 117, that is, placed on the floor 118. In manycases, the unit main body 100 is arranged along a wall 120. The floor118 has double flooring structure. An opening hole 118 a is formed inthe floor 118 so as to be communicated to an underfloor space 119.

Inside the unit main body 100, an air cleaning filter 103 is removablymounted to the unit air inlet 101.

The floor 118, on which the unit main body 100 is placed, has aplurality of opening portions formed in portions thereof on a downstreamside of a flow of the air-conditioned air. The air-conditioned air issupplied, through the opening portions, to a computer storage rack andan air conditioning apparatus that is separately placed, and thuscomputers are cooled. That is, in the entire room, there is formed acirculating flow including an airflow flowing upward from below aroundan object to be cooled.

On a downstream side of the unit air inlet 101, a heat exchanger 104, adrain pan 114 for collecting condensed water, and two blower fans 107are arranged. The drain pan 114 for collecting condensed water isarranged below the heat exchanger 104, and the blower fans 107 arearranged below the drain pan 114.

The heat exchanger 104 includes two heat exchanger forming sections 104a each having a flat-plate-like shape, and is supported by a bracket 104b. The heat exchanger forming sections 104 a are arranged in a V-shapeso that an interval between end port ions of the heat exchanger formingsections 104 a on a unit upper side is larger than an interval betweenend portions of the heat exchanger forming sections 104 a on a unitlower side. A coupling plate 105 is mounted between the end portions ofthe pair of heat exchanger forming sections 104 a on the unit upperside, and fixing plates 106 are mounted to the pair of heat exchangerforming sections 104 a on both sides of the unit (on both front and backsides of the drawing sheet of FIG. 2). With this, the air sucked intothe unit is accelerated to reach the blower fans 107 after flowingthrough the heat exchanger forming sections 104 a.

The heat exchanger 104 is connected, through a refrigerant pipe, to anoutdoor unit (not shown) including a compressor arranged therein.Further, on a downstream side portion of each of the heat exchangerforming sections 104 a, a plurality of sub-drain pans 113 are arranged.With this, even if dew condensation water drips down from the heatexchanger 104, drops of water are collected in the sub-drain pans 113,and can be discharged into the drain pan 114.

As illustrated in FIG. 3, the blower fans 107 each include an impeller108, a motor 109, a fan casing 110, and a motor support 111. The twoblower fans 107 are arranged with an interval in a widthwise direction.More specifically, the two blower fans 107 are arranged so that adjacentfan casings 110 described later are separated from each other. Further,as an example, the two blower fans are controlled so as to have mutuallydifferent numbers of revolutions of the fans. Note that, in a specificexample of the first embodiment, the two blower fans are provided, butthis embodiment and the present invention are not limited thereto. Threeor more blower fans may be provided.

Next, details of the blower fans are described. FIG. 4 is a perspectiveview illustrating one of the blower fans of the air conditioningapparatus of FIG. 1. FIG. 5 is a cross-sectional view taken along theline V-V of FIG. 2. FIG. 6 is a cross-sectional view taken along theline VI-VI of FIG. 5. FIG. 7 is a view schematically illustrating anairflow formed inside the blower fan of FIG. 4.

The impeller 108 is a turbofan that sucks the air from an upper portionthereof and blows out the air radially outward. Specifically, theimpeller 108 includes a plurality of blades 108 a, a side plate 108 bhaving a ring shape, and a main plate 108 c. As illustrated in FIG. 2,the impeller 108 is arranged so that a rotation axis thereof is directedto a height direction H (an up-and-down direction, or a verticaldirection) of the unit. The impeller 108 is arranged so that the sideplate 108 b, the plurality of blades 108 a, and the main plate 108 c areprovided in the stated order from the unit upper side.

Each of the plurality of blades 108 a is formed so that not a radiallyinner portion but a radially outer portion thereof is positioned at therear in a fan rotation direction RO. The plurality of blades 108 aextend in the height direction between the side plate 108 b and the mainplate 108 c.

The side plate 108 b is positioned on an upstream side of the pluralityof blades 108 a, that is, on a fan air inlet 107 a side in the impeller108. The side plate 108 b has a ring shape having an opening formed in acenter thereof in plan view, and functions as a wall through which theair is sucked and guided. On the other hand, the main plate 108 c ispositioned on a fan air outlet 107 b side in the impeller 108, and isconnected to and astride lower ends of the plurality of blades 108 a. Arotation shaft 109 a of the motor 109 for rotationally driving theimpeller 108 is fixed to the main plate 108 c.

An outer diameter φDs of the side plate 108 b of the impeller 108 islarger than an outer diameter φDm of the main plate 108 c of theimpeller 108. Further, regarding an outer diameter of each of the blades108 a, an outer diameter φDb1 on the side plate side in an extendingdirection of the rotation shaft 109 a is larger than an outer diameterφDb2 on the main plate side.

The fan casing 110 includes a frame body 110 a formed into asubstantially rectangular parallelepiped shape, a bell-mouth 112 mountedto the frame body 110 a, and four side wall surfaces 110 b. Thebell-mouth 112 is mounted to an upper portion of the frame body 110 a,and has the fan air inlet 107 a formed therein so as to be communicatedto an impeller air inlet 108 d. The four side wall surfaces 110 b areremovably mounted to corresponding side portions of the frame body 110a, respectively.

With this, it can be considered that an upper surface of the fan casing110 having a substantially rectangular parallelepiped shape is formed bythe bell-mouth 112, and that four side surfaces of the fan casing 110are formed by the four side wall surfaces 110 b. A further radiallyouter side of an impeller air outlet 108 e of the impeller 108 iscovered by side surfaces of the fan casing 110, and the side surfaces ofthe fan casing 110 can be opened and closed through mounting anddismounting of the side wall surfaces 110 b.

Further, an opening is formed in a region corresponding to a bottomsurface of the fan casing 110, which also serves as a surface opposed tothe bell-mouth 112. The opening functions as the fan air outlet 107 b.As illustrated in FIG. 2, the fan air outlet 107 b is formed so as to becommunicated to the unit air outlet 102. That is, the fan casing 110 hasthe fan air inlet 107 a formed in an upper surface thereof, and has thefan air outlet 107 b formed in a lower surface thereof.

Note that, the motor support 111 is positioned on the fan air outlet 107b side of the main plate 108 c of the impeller.

In the air conditioning apparatus configured as described above, whenthe impeller 108 is rotationally driven by the motor 109 about arotation center O, the air in the room 117 is sucked into the airconditioning apparatus through the unit air inlet 101. The air, fromwhich dust is removed by the air cleaning filter 103, is cooled anddehumidified by the heat exchanger 104, guided to the bell-mouth 112serving as the fan air inlet 107 a of the blower fan 107, and suckedtoward the impeller 108 from above. As illustrated in FIG. 7, the suckedair is subjected to actions of the plurality of blades 108 a, and thusis blown out from sides of the impeller 108, that is, from the impellerair outlet 108 e. In addition, the sucked air is deflected downward bythe side wall surfaces 110 b of the fan casing 110. That is, the airsucked toward the impeller 108 is once blown out toward the sidesdifferent from the fan air outlet 107 b, and is deflected to the fan airoutlet 107 b under the actions of the side wall surfaces 110 b of thefan casing 110. Then, the sucked air flows through the unit air outlet102 into the underfloor space 119.

According to the air conditioning apparatus of the first embodimentconfigured as described above, the following excellence can be obtained.First, in the air conditioning apparatus according to the firstembodiment, the air sucked toward the impeller is once blown out towardthe sides different from the fan air outlet, and is deflected to the fanair outlet under the actions of the side wall surfaces of the fancasing, to thereby be sent from the unit air outlet. Accordingly, ascompared to a case where the air is directly blown out from the impellertoward the unit air outlet, velocity of the air flowing out from theunit air outlet is satisfactorily reduced in the first embodiment.Accordingly, velocity of the air flowing into the underfloor space islow, and hence the air is prevented from colliding with a bottom surfaceof the underfloor space while keeping a high-velocity flow. Thus,airflow resistance can be reduced, and particularly in a property thatdoes not allow a long distance to the bottom surface of the underfloorspace and has a small-height underfloor space, an effect of reducingairflow resistance can be significantly obtained, which is effective.Accordingly, finally, power consumption of the motor can be reduced, andenergy saving can be achieved. Further, the blown-out air flows at lowvelocity, and hence it is possible to reduce a problem in that theblown-out air stirs up dust underneath the floor. That is, it ispossible to obtain an energy-saving, silent, and high-quality airconditioning apparatus.

In addition, according to the first embodiment, in a mode in which eachof the blower fans is arranged below the heat exchanger, the fan airinlet is formed in the upper surface of the fan casing. Accordingly,unlike a case where the fan air inlet is formed in a side surface of thefan casing, it is possible to prevent local concentration of theairflow. Therefore, when the air is sucked from the heat exchangerarranged above the fan air inlet, wind velocity is equalized over thefan air inlet, and is not increased locally. Accordingly, reduction innoise level can be achieved.

Further, the outer diameter φDs of the side plate of the impeller islarger than the outer diameter φDm of the main plate of the impeller.Thus, when the airflow from the impeller air outlet is deflected by theside wall surfaces of the fan casing, an airflow path is enlarged on themain plate side of the impeller, and hence the airflow is easilydeflected. With this, airflow resistance can be further reduced, andpower consumption of the motor can be further reduced.

Further, the outer diameter φDb1 of each of the blades on the side plateside is larger than the outer diameter φDb2 of each of the blades on themain plate side, and hence an air blowing amount in a side-plate-sideregion of each blade can be increased as compared to an air blowingamount in a main-plate-side region of each blade. Thus, the airflow iseasily deflected toward the fan air outlet. As a result, it is possibleto reduce power consumption of the motor, and it is possible to reducenoise caused when the airflow collides with wall surfaces whendeflected. That is, also with this, it is possible to obtain an airconditioning apparatus capable of saving energy and reducing noiselevel.

Further, the plurality of blower fans are provided, and hence the aircan be sucked in a large range. Even when the heat exchanger has anelongate body, a wind velocity distribution in the heat exchanger can beequalized. Accordingly, the heat exchanger can be employed effectively,and it is not necessary to increase an air blowing amount uselessly.Also with this, power consumption of the motor can be reduced, andreduction in noise level can be achieved.

Further, the plurality of blower fans are arranged with an interval inthe widthwise direction, and hence it is possible to prevent theadjacent fans from scrambling for the airflow toward the fan air inlets.With this, airflow resistance can be reduced, and the airflow can besucked into the heat exchanger in a large range. Also with this,reduction in power consumption of the motor and reduction in noise levelcan be achieved.

In a case where the plurality of blower fans are controlled so as tohave mutually different numbers of revolutions of the fans, it ispossible to suppress beat noise between adjacent fans caused in a casewhere the fans are controlled so as to have the same number ofrevolutions (for example, in a case where the plurality blower fans aredriven by one motor), and hence audibility can be enhanced. Further, ina case where an installation position is set to a corner section of aroom so that an air outlet space for one of the blower fans is narrowand an air outlet space for another one of the blower fans is wide, whenthe fans are controlled so as to have the same number of revolutions,there is a fear in that airflow resistance of one of the blower fansbecomes extremely high, to thereby cause increase in power consumptionof the motor. However, the fans are controlled so as to have mutuallydifferent numbers of revolutions of the fans, and thus airflowresistance can be adjusted. Further, power consumption of the motor canbe reduced.

The fan casing includes the frame body and at least one side wallsurface removably mounted to the frame body, and hence a side surface ofthe fan casing can be opened and closed. Accordingly, there is anadvantage in that replacement work is easily performed even if theimpeller or the motor is broken or damaged. Further, strength can beensured owing to the frame body, and hence the fan casing does not needto be thick entirely. Thus, weight and an amount of a material can bereduced. In addition, a material for a part of wall surfaces forming thefan casing can be changed or varied from a material for the frame bodyand the other wall surfaces. For example, when a reinforced transparentresin is employed as a material for a part of wall surfaces, anoperation state of the fan can be easily checked only through removal ofa side plate of the main body, and hence a construction property and amaintenance property can be enhanced.

Further, the motor support is positioned closer to the side on which thefan air outlet is formed than the main plate of the impeller. That is,this leads to separation of the motor support from the fan air inlet,and thus it is possible to obtain a mode in which the air passes aroundthe motor support at a stage where the wind velocity is reduced in aroute of the airflow from the fan air inlet to the fan air outlet. Alsowith this, reduction in airflow resistance and suppression ofdegradation of noise level can be achieved. Further, the airflow towardthe fan air outlet can be deflected by the motor support toward the fanair outlet. That is, the motor support can exert a function ofsupporting the motor, and a function as an air guiding plate.

Further, side surfaces of the fan casing include at least one flatsurface. As an example of the fan casing, in the first embodiment, thefan casing exhibits a rectangular shape in plan view. Regarding this,for example, in a case where the fan casing has a cylindrical shape anda side wall surface of the fan casing exhibits a circular shape in planview, the airflow circles, and hence the airflow is not smoothlydeflected toward the fan air outlet by the side wall surface of the fancasing. As a result, there is a fear in that an air blowing amount isreduced, and thus power consumption of the motor may be deteriorated. Onthe other hand, in the first embodiment, as described above, the fancasing exhibits a rectangular shape in plan view, and hence foursurfaces and four corners are secured on the side surfaces of the fancasing. The airflow blown out from the impeller air outlet is preventedfrom circling, and is effectively and reliably deflected toward the fanair outlet by large flat surfaces serving as the side wall surfaces.Accordingly, also with this, it is possible to obtain an effect ofreducing power consumption of the motor.

Further, the heat exchanger has a V-shape, that is, has a shapeincluding at least one bent portion. Thus, an area of the heat exchangercan be enlarged, and heat transferring performance is enhanced.Accordingly, even in a case of the same air blowing amount, a heatexchange amount can be increased. Therefore, in a case of the same heatexchange amount, an air blowing amount can be further reduced, and powerconsumption of the motor can be reduced.

Second Embodiment

Next, an air conditioning apparatus according to a second embodiment ofthe present invention is described. FIG. 8 is a view illustrating thesecond embodiment and corresponding to FIG. 5. Note that, the secondembodiment has the same configuration as that of the above-mentionedfirst embodiment except for components to be described below.

A fan casing 210 of a blower fan 207 according to the second embodimentincludes a pair of rounded portions 223 a and a pair of chamferedportions 233 b at portions thereof corresponding to corners of arectangular shape with reference to the rectangular shape of the fancasing 110 in plan view.

Also in the second embodiment, the same advantage as that of the firstembodiment can be obtained. Further, also in the second embodiment, theside surfaces of the fan casing include at least one flat surface, andhence similarly to the first embodiment, the airflow blown out from theimpeller air outlet is prevented from circling, and is effectively andreliably deflected toward the fan air outlet by large flat surfacesserving as side wall surfaces. In addition, in the second embodiment, atleast one chamfered portion is formed at a portion of the fan casingcorresponding to a corner of a rectangular shape with reference to therectangular shape of the fan casing 110 in plan view. Accordingly,piping and wiring can be provided in a space formed outside thechamfered portion of the fan casing, and upsizing of a dimension of theunit can be suppressed. That is, it is possible to obtain an airconditioning apparatus that is easily downsized while realizingreduction in power consumption of the motor along with reduction inairflow resistance.

Third Embodiment

Next, an air conditioning apparatus according to a third embodiment ofthe present invention is described. FIG. 9 is a view illustrating thethird embodiment and corresponding to FIG. 2. Note that, the thirdembodiment has the same configuration as that of the above-mentionedfirst or second embodiment except for components to be described below.As an example, FIG. 9 illustrates a case where the third embodiment isimplemented in combination with the above-mentioned first embodiment.

In the third embodiment, a heat exchanger 304 includes the two heatexchanger forming sections 104 a arranged in an inverted V-shape. Belowa lower end of each of the heat exchanger forming sections 104 a, adrain pan 314 is provided.

Also in the third embodiment, the same advantage as that of thecorresponding first or second embodiment can be obtained. In addition,in the third embodiment, the heat exchanger has an inverted V-shape, andhence it is possible to realize such a layout that the fan air inlet isarranged in a space on a side of an interval between the heat exchangerforming sections. The drain pan is not positioned near the fan air inletnor directly above the fan air inlet, with the result that reduction inairflow resistance and suppression of a drift are accelerated. Also withthis, reduction in power consumption of the motor and reduction in noiselevel can be achieved.

Further, the above-mentioned feature of the third embodiment is notlimited to forming the heat exchanger into an inverted V-shape. FIG. 10is a view illustrating a modified example of the third embodiment andcorresponding to FIG. 3, and FIG. 11 is a view illustrating the modifiedexample of the third embodiment and corresponding to FIG. 2.

As the third embodiment, a heat exchanger 404 includes four heatexchanger forming sections 104 a arranged in an M-shape. Below a lowerend of each of the heat exchanger forming sections 104 a, a drain pan414 is provided. Note that, the above-mentioned M-shape is viewed from alateral side orthogonal to such an aligning direction of the blower fansthat the plurality of blower fans appear to overlap each other.

Also in this modified example, similarly to a case where the heatexchanger having an inverted V-shape illustrated in FIG. 9 is provided,the drain pan is not positioned near the fan air inlet nor directlyabove the fan air inlet, and thus reduction in airflow resistance andsuppression of the drift can be achieved.

Although the details of the present invention are specifically describedabove with reference to the preferred embodiments, it is apparent thatpersons skilled in the art may adopt various modifications based on thebasic technical concepts and teachings of the present invention. Forexample, a single blower fan may be used.

REFERENCE SIGNS LIST

-   -   100 unit main body, 104, 304, 404 heat exchanger, 104 a heat        exchanger forming section, 107, 207 blower fan, 107 a fan air        inlet, 107 b fan air outlet, 108 impeller, 108 a blade, 108 b        side plate, 108 c main plate, 108 d impeller air inlet, 108 e        impeller air outlet, 109 motor, 110, 210 fan casing, 110 a, 210        a frame body, 110 b side wall surface, ill motor support.

1. An air conditioning apparatus, comprising: a unit main body; a heatexchanger; and at least one blower fan, wherein the heat exchanger isarranged on an upstream side of the blower fan, wherein the blower fancomprises an impeller, a motor, and a fan casing, wherein the impellercomprises a turbofan that sucks air from an upper portion thereof andblows out the air radially outward, wherein a rotation axis of theimpeller is directed to a unit height direction, wherein the fan casinghas a fan air inlet formed in an upper surface thereof, and has a fanair outlet formed in a lower surface thereof, and wherein an impellerair outlet of the impeller is covered by side surfaces of the fancasing, wherein the impeller comprises a plurality of blades, a sideplate having a ring shape, and a main plate, wherein the side plate ispositioned on the fan air inlet side, and the main plate is positionedon the fan air outlet side, and wherein an outer diameter (φDs) of theside plate is larger than an outer diameter (φDm) of the main plate. 2.An air conditioning apparatus according to claim 1, wherein the blowerfan is arranged below the heat exchanger. 3-4. (canceled)
 5. An airconditioning apparatus according to claim 1, wherein the airconditioning apparatus comprises a plurality of blower fans.
 6. An airconditioning apparatus according to claim 5, wherein the plurality ofblower fans are arranged with an interval in a widthwise direction. 7.An air conditioning apparatus according to claim 5, wherein theplurality of blower fans are controlled so as to have mutually differentnumbers of revolutions of the fans.
 8. An air conditioning apparatusaccording to claim 1, wherein the fan casing comprises a frame body, andat least one side wall surface is removably mounted to the frame body.9. An air conditioning apparatus according to claim 1, wherein theblower fan comprises a motor support, and wherein the motor support ispositioned on the fan air outlet side of the main plate of the impeller.10. An air conditioning apparatus according to claim 1, wherein the sidesurfaces of the fan casing comprise at least one flat surface.
 11. Anair conditioning apparatus according to claim 10, wherein the fan casingcomprises at least one chamfered portion, with reference to arectangular shape of the fan casing in plane view, at a portioncorresponding to a corner of the rectangular shape.
 12. An airconditioning apparatus according to claim 1, wherein the heat exchangerhas a shape comprising at least one bent portion.
 13. An airconditioning apparatus according to claim 1, wherein the heat exchangerhas an inverted V-shape or an M-shape.
 14. An air conditioningapparatus, comprising: a unit main body; a heat exchanger; and at leastone blower fan, wherein the heat exchanger is arranged on an upstreamside of the blower fan, wherein the blower fan comprises an impeller, amotor, and a fan casing, wherein the impeller comprises a turbofan thatsucks air from an upper portion thereof and blows out the air radiallyoutward, wherein a rotation axis of the impeller is directed to a unitheight direction, wherein the fan casing has a fan air inlet formed inan upper surface thereof, and has a fan air outlet formed in a lowersurface thereof, and wherein an impeller air outlet of the impeller iscovered by side surfaces of the fan casing, wherein an outer diameter(φDb1) of each of the blades on the side plate side is larger than anouter diameter (φDb2) of each of the blades on the main plate side.